A pitcher throws a baseball with mass=.145kg straight up with initial v=25 m/s

a) How much work has gravity done on the ball when it reaches h=20m above pitcher's hand?
b) Using work-energy theorem, calculate speed of baseball at h=20m above pitcher's hand
c) Does the answer to part b depend on weather the ball is moving up or down at a height of 20m? Please explain.

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